Climate change and broadacre livestock production across southern Australia. 2. Adaptation options via grassland management

Abstract

Climate change is predicted to cause a significant reduction in the productivity of grasslands and the livestock industry across southern Australia. We have used the GRAZPLAN biophysical simulation models to assess a range of pasture management practices as adaptation options under the SRES A2 global change scenario. The modelling analysis spanned four dimensions: space (25 representative locations), time (2030, 2050, 2070, and a historical reference period of 1970–99), livestock enterprises (five), and management (four adaptation options at different levels). Climate projection uncertainty was taken into account by considering climates from four global climate models. The effectiveness of adaptation options varied widely among enterprises and locations, over time, and under the four projected future climates. Increased soil fertility by adding phosphorus and addition of an area of lucerne to the feed-base were predicted to have the greatest effect in recovering from the negative impact of climate change on profitability. In high-rainfall zones in particular, and compared with the historical period, the most profitable option could return the profitability of livestock production systems to historical levels at 68%, 52%, and 32% of the representative locations at 2030, 2050, and 2070, respectively. At 2030, increased soil fertility, adding lucerne to the feed-base, and confinement feeding in summer recovered overall profit fully at 52%, 28%, and 12% of locations. Removing annual legumes in an attempt to preserve ground cover was ineffective as an adaptation to changing climate. For the majority of location × livestock enterprise combinations, there was at least one individual incremental adaptation that could recover the declines in the profitability at 2030, but effectiveness decreased over time after 2030. It is unlikely that the examined single climate change adaptations to the feed-base of southern Australian livestock production systems can return them to profitability in the second half of the century.